John lyall



(No Model.)

' J. LYALL.

MACHINE FOR CUTTING METAL OVALS.

No. 324,331. Patented Aug. 11. 1885.

Nv PETERS. Phnb-Utlmgnphen Wishlflghm. D. C.

UNITED STATES PATENT OFFICE.

JOHN LYALL, OF GOVAN, COUNTY OF LANARK, SCOTLAND.

MACHINE FOR CUTTING METAL OVALS.

SPECIFICATION forming part of Letters Patent No. 324,331, dated August11, 1885.

Application filed February 2, 1885. (No model.) Patented in EnglandApril 19, 1884, No. 6,574; in France January 20, 1885, No. 166,543, andin Germany January 24, 1885, No. 32,161. v

To all whom it may concern:

Be it known that 1, JOHN LYALL, residing at Govan, in the county-ofLanark, Scotland, and a subject of the Queen of Great Britain andIreland, have invented certain Improved Apparatus for Cutting Oval Holesin Metal Plates, of which the following is a specification.

My invention relates to improved apparatus for cutting oval holesinmetal plates such, for example, as the man-hole and mud- Lole doorwaysof steanrboilers.

The invention is illustrated in the accompanying drawings, in whichFigure 1 is an elevation, and Fig. 2 is a plan, of a modification of myimproved apparatus for cutting oval holes.

The improved apparatus. comprises a head or center block, A, which isbolted or otherwise secured to the plate B, in which the oval hole is tobe cut. In the upper side of this head or block are out two grooves, cand (1, formed of inverted V or T shape, and crossing each othercentrally at right angles. The grooves c d may be. in the same plane;but are by preference formed so that the up- .per surface of the one isin the plane of the bottom surface of the other, so that the slides Oand D, with which they are fitted, may freely cross each other. Oneslide is fitted within each groove, and may be made in the form of abolt-head, O or D, corresponding in shape to the section of the groove 0or d, and formed or fitted with a pin or bolt, 0 or d, passing outperpendicular to the groove through-a bush, E, fitted to slide and turnfreely on the upper side of the head A, the bush being secured to thehead by nuts 6, or equivalent fastenings, on the ends of the bolts 0 D.This bush E is fixed to or formed 011 an arm, F, extending out laterallyon both sides from the head, and this arm is fitted with a handle orcrank-pin, by means of which it is rotated, or it is operated by adriving-arm, G, on the spindle G, of a vertical boring-machine, theplate being secured between the head A and the table B of the vertical.By the rotation of the bush E the slides O D are traversed back andforth in their grooves c d, and they constrain the motion of the bushand arm, so that the path traversed by any point in the arm F is that ofan ellipse or oval. If

a cutting-tool be fixed in the arm F perpendicular to the plate to whichthe head is fixed, it may be made to cut out an oval opening in theplate round the head A as a center, and the major and minor axes of theoval will depend on the distance apart of the centers of the slides orbolts 0 D. On one end of the cross-arm F is formed a boss, H, whichcarries a spindle, I, fitted with a radial slotted arm, J, in which atool-holder, K, is secured. The tool-holder K is adjustable radially inthe slotj, so that it may be moved out from or toward the center, toregulate the size of hole which is to be cut by the tool carried in thetool-holder. The tool It is fed forward in a line perpendicular to theplate B to be cut, by means of a screw, Z, which acts on the spindle I,carrying the slotted arm 70 J and tool-holder K, and which is turned bya hand-wheel or by a -star-wheel, L, or similar device acted on at eachrevolution by a fixed stop. The tool 70 cuts a groove in the plate B,and this groove is deepened as the 5 tool is fed forward until the plateis cut through.

a By providing several .sets of interchange; able bushes E, bored withthe holes to fit over the slide-bolts O D at different distances 8oapart, the relative lengths of the major and minor axes of the oval maybe Varied.

The apparatus may be driven, as indicated, from a vertical .boringmachine, or from a lathe or similar machine arranged to act on the armF, which rotates the bush; or it may be operated by hand, in whichlatter case I prefer to secure on the head A a bracket carrying a trainof wheels through which the motion of a hand-crank is imparted to the 0arm F, the object of the gearing being to increase the power.

What I claim is- The combination of the tool-carrying arm F, bush E,bolts or slides C D, and grooved 5 center-block, A, substantially as andfor the purpose set forth.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

JOHN LYALL. Witnesses: W. R. M. ClHoMsoN, WALLAcn FAIRWEATHER.

